Portion of an image for a display screen



FIG. 1 is a front view of a portion of an image for a display screen showing our new design; and,

FIG. 2 is a front view of a second embodiment of our new design.

The broken line drawing of a display screen in both views is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a portion of an image for a display screen, as shown and described. 